Mega Steve:I liked his gauss gun better. While the model he made was not super practical, I can see that kind technology being very useful in punching through body armor and such.

You can stab through most bullet proof vests. They only work because lead and brass are soft. AP rounds have a steel core which, as the name implies, pierces the armor. With larger shells, like the infamous yet fictional .88 magnum, you can also pierce things with pure kinetic energy.

Or, just look in a book on knights and pick something pointy. A 300lb test crossbow with a bodkin point (think ice pick) would probably do the trick if it's just going through armor on a range. Using one in war would be ill advised.

A gauss gun is really just a big solenoid. You can fire a projectile fairly fast using only magnets, which is really cool. But the size of the capacitor bank you'd need to shoot a big one and the time between shots would make it a very impractical device as a weapon. Railguns need to be mounted on a boat and hooked to a nuclear reactor for similar power reasons.